Thermostatic temperature-controlling device for electric ovens.



v TJJH RDING. v THERMOSTA-TC IEMFERTUKE CONTROL'LING DEVICE FOR ELECTRIC OVENS. 4 mcma maj mua. sz. 1383507.- Patented Nov. 5, 1918.

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F. HARDING. THERMOSTATIC TEMPERATUBE CONTROLLING D E VICE FOR-ELETRIC OVENS. APPLICATION FILED JAN.13, !917.

1 ,283,507b Patented Nov. 1918.

2 SHEETS-SHEEI 2.

Ha/rai in UNITEB i FREDEBIG T,

THEnMosrATIc rnmrnnzirnnn eoir i WE specific-&tiran of ?atent Petented Nov-e Mi&

Application filed January 13,191?. Serial o. l t-2,168.

.mprovements in thermostatic temperature controlling devices for electrc' ovens and 'the rincipal object of the invention is to provide" a device which is adapted to automatically'cut out and cut in an electric circuit .when the temperature of an oven rises or falls above or below a predetermined point. V

Another object of the invention is to provide a device which may be adjusted to increase or decrease the temperature at which the controller operates. v

' A further object of the invention is to provide a combined indicator by which the temperature may be controlled which also serves as a lock to hold the door of the oven closed.

A still further object of the invention is to provide a novel form of thermostat which may be located within the oven so as to insure the proper operation of the device.

Still another object of the invention is to provide a device for actuating a novel form of switch which is capable of being used in connection with either an alternating or direct current without danger of the contact being accidentally broken through the alternations when the device is used on an alternating current.

o en sho ng th s device emilia sie e 2 is e fragnentery -horizontei seotionai view through e portion of en oven showing thi device applied thereto.

3 is showing the method of assembling the de vice;

s e fregmentary view in elevetion Fig. 4 is diegremmetic view of the 'device showing the method of using the same 'with an elternating circnit.

Fig, 5 is a view showing the devicensed in' connection with a direct current circnt,

and u Fig. 6 is a fregmentar v 'front eievation of the oven door showing the diel plote and indeetor hand.

Referrng to the drawngs i designates electric oven of any suitable construotion' provided with a door 2. This door is provided With e. suitable fienge 3 which is formed centrally with a recess i'. Aj suitable diel plate 5 which is preferably semi-circu-,

ler in plan is proyided and formed with a recess which ahnes wth the recess i heroinbefore referred to at e point 'centrally of itsstraight edge. A series of greduetions 6 are forme& on the enter face oi the diel plote as cieariy illnstrnted in the dmvvin s. A' iongitu inally through one of the walls of the oven 1 and. lextending thron 'h the bore 7 is a rod 8 ear .suitable bore 7 extends ryin at one end a pointer 5) which is pro-- vide` with a thumb piece 10 by means which the pointer and rod are rotated. red as shown in the drawngs extends beyond the end of the wall through which the bore 7 extends and is arrengeq to position the hand 9 in' coperative 'relaton Wth the fil dial 5. The end of the red 7 op osite thot carrying the hand 9 is threads: and provided With a mit 11 against which the for adjusting the contact sprin is sn@ ported. A clamp nut 12 is three` cd on the extreme end of the rod 8 and coperetes with the nut 11 in holding 'the cem in proper place. I

The cam above referred to comprises .nrcuate body 13 having one edge inciinecl as et 1%. The central portion of the opposite edge an inwardly er ztending portion 15 having' an ear 16 forrned thereon which is bent 'right angles to the plane of the cem. end "provided with an opening for'the recent of the red 8. .This ear is iitted on *I between the nnts and it Evil of said body is :provided with i hinding screw 49 from which the current is ied through a wire 50 to the binding screw 51 on the arm 43.. A suitable Shunt Wire 52 leads from the binding screw 49 to one of the magnets and the opposite terminal of said magnet is connected by a' wire 53 to the opposite magnet which in turn is connected by a Wire 54 to the' contact 23 of the-circuit Closer;` The arm 29 of the circuit closer is connected by a wire 55 through a suitable resistance lamp to the opposite line Wire which is also directly connected to the heating element. The opposite terminal of said heating element is 'connected by a Wire 56 to the binding screw 47 and thus it Will' be seen that the block 45 Will be charged.

From the foregoing it will be seen that when the magnets are energized by the closing of the circuit through the circuit closer the armature Will be swung on its pivot so as to cause'the blocks 44 and to move into contact the`reby completing the circuit through the heating element.

While in the foregoing there has been shown and described the preferred embodiment of this invention it is to be understood .that such changes nay be made in the combination and arrangement of parts as will fall within the spirit and scope of the invention as claimed.

' What is claimed is 1. In a thermostatic circuit closer, a tube having a relatively low expansion coeflicient under the influence of heat, a rod extending through said tube having a relatively high coefiicient or" expansion, the inner end of the rod being attached to the inner end of the tube, a tongue on the tube at its outer end, a tongue on the outer end of the rod, the tongues being attached together Whereby when the tube and rod are afiected by .heat

the tongues will bend and actuate a thermostat.

2. in a thermostatic circuit closer, a bendable tongue which bends under the influence of heat, a contact arm carried by said tongue, a permanent magnet in the path of movement of said arm, said magnet forming a contact for coperation With the arm, a spring plate supporting the magnet and a rotatable cam adapted to move the free end of the spring plate to adjust the magnet 'with relation to the arm.

3. In a thermostatie circuit closer, a bendable tongue which bends under the influence of heat, a contact arm carried' by said tongue, a 'permanent magnet in the path of et fo rm-.

movement of said arm said ma ing a contact for coperation Wit the arm, a spring plate supporting the magnet, a cam for adjusting the plate relatively to the arm, a pointer for Operating the cam and a dial coperating with the pointer to indicate the various positions of ad'ustment.

In testimony whereo I afiix my signature in presence of two witnesses.

FREDERIC T. HARDING. 

